Net inspector: columns initialise badly on board load

Description

When loading a PCB in Pcbnew, the net inspector dialog gets all the columns except the last set to near-zero width, and the the last one is very wide and goes off the right side.

Steps to reproduce

1. Open the video demo
2. Look at the net inspector dialog
3. Try to adjust any column is awkward, trying to get all of them is tedious
4. Reload pcbnew
5. The columns are reset to how they were at first

netinspect-2025-01-01_22.18.27

Standalone Pcbnew with nothing loaded seems sensible:

KiCad Version

Application: KiCad PCB Editor x86_64 on x86_64

Version: 9.0.0-rc1-275-gbbea339279, debug build

Libraries:
	wxWidgets 3.2.6
	FreeType 2.13.3
	HarfBuzz 10.1.0
	FontConfig 2.15.0
	libcurl/8.11.1 OpenSSL/3.4.0 zlib/1.3.1 brotli/1.1.0 zstd/1.5.6 libidn2/2.3.7 libpsl/0.21.5 libssh2/1.11.0 nghttp2/1.64.0 nghttp3/1.6.0

Platform: EndeavourOS, 64 bit, Little endian, wxGTK, X11, , x11
OpenGL: Intel, Mesa Intel(R) Iris(R) Xe Graphics (ADL GT2), 4.6 (Compatibility Profile) Mesa 24.3.1-arch1.3

Build Info:
	Date: Jan  1 2025 22:08:20
	wxWidgets: 3.2.6 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.86.0
	OCC: 7.8.1
	Curl: 8.11.1
	ngspice: 43
	Compiler: GCC 14.2.1 with C++ ABI 1019

Build settings:
	KICAD_USE_EGL=ON
	KICAD_IPC_API=ON
	KICAD_STDLIB_DEBUG=OFF
	KICAD_STDLIB_LIGHT_DEBUG=OFF
	KICAD_SANITIZE_ADDRESS=OFF
	KICAD_SANITIZE_THREADS=OFF

Locale: 
	Lang: en_GB
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)